Reynolds, Osborne

[re nuhldz] (1842–1912) British engineer and physicist: gave definitive analysis of turbulent flow.

Reynolds studied mathematics at Cambridge, before being appointed as the first professor of engineering at Owens College (now Manchester University), where one of his students .

Reynolds was one of the outstanding theoretical engineers of the 19th-c. Most of his work concerned fluid dynamics, problems such as the flow around ships’ propellers, vortex production by moving bodies and the scaling up of test results from models in which he used dyes to reveal flow patterns and vortices. He is remembered particularly for his work on the turbulent and laminar flow of liquids, and for defining (in 1883) a dimensionless quantity, the Reynolds number, to determine the type of flow regime. The Reynolds number depends upon the viscosity, velocity, density and linear dimensions of the flow. He also carried out definitive work on lubrication, explained why radiometers rotate and performed a classic determination of the mechanical equivalent of heat.